Fuel injection devices use a pressure regulator, which is disposed downstream of a fuel pump in terms of the direction of supply. The pressure regulator regulates the pressure (system pressure) in the fuel system. It requires installation space in the engine compartment. Exacting requirements will be placed on the installation in terms of leakproofness.
The fuel pump, which serves to supply fuel and to effect the pressure buildup in the fuel system, for example according to German patent application DE-A-3900264, is equipped with a seat valve which opens when subjected to overpressure, and which is disposed in a bypass that leads from the compression side to the intake side. In addition, a check valve is provided on the outgoing side of the pump's drive motor, through which fuel flows, in order to avoid a return flow of the fuel when the supply is static. In other words, several measures are taken in the fuel system for monitoring the pressure.